1. Field of the Invention
The present invention relates to the retracting of a head from a disk in a hard disk drive.
2. Background Information
Hard disk drives contain a plurality of magnetic heads that are coupled to rotating disks. The heads write and read information by magnetizing and sensing the magnetic fields of the disk surfaces. Each head is attached to a flexure arm to create a subassembly commonly referred to as a head gimbal assembly (“HGA”). The HGA's are suspended from an actuator arm. The actuator arm has a voice coil motor that can move the heads across the surfaces of the disks.
When a drive is not in use the heads are typically moved off of the disks. For example, the heads can be moved onto a mechanical ramp. The drive may include a magnet that applies a magnetic force to the actuator arm and holds the heads in a retract position. As the actuator arm approaches the magnet the magnetic force tends to pull and accelerate the arm. This can lead to an undesirable crashing of the arm into the magnet. To counter the pulling magnetic force of the magnet a reverse current can be applied to the voice coil motor to slow down the arm. Present slow down schemes create an audible noise. It is generally undesirable to have an audible noise emanating from a hard disk drive.